DeBAKEy CARDIOvASCuLAR JOuRNAL - Methodist Hospital

Figure 1. Lazar
Greenfield, vascular
surgeon
positive impact on patient welfare. One such example
is the Kimray-Greenfield inferior vena cava filter that
is used clinically to prevent clots passing from the
legs to the lungs. Dr. Lazar Greenfield (Figure 1) was
prompted by a case of pulmonary embolus in a young
trauma patient. After opening the chest and performing
a pulmonary embolectomy, the patient died. Dr.
Greenfield sought better techniques to prevent pulmonary
embolus and asked Garman Kimmell (Figure 2),
an entrepreneur-inventor from the oil and gas industry,
for his help. Kimmell recognized the similar problem of
sludge in oil pipelines and how a conical filter trapped
the sludge at its center while still allowing flow around
it on the sides. Together they designed a prototype and
tested it in animals before implanting it in patients in the
early 1970s. The modern descendant is the stainless steel
Greenfield filter that has been implanted in more than
200,000 patients to date (Figure 3).
“Great invention is always metaphor,” says John Abele,
a co-founder of Boston Scientific Corporation, which
has manufactured the
Greenfield filter since
it acquired Kimmell’s
medical-device company
in 1980. “you look at the
problem, and then you
try to connect it to other
areas which may have
nothing to do with the
problem you’re working
on.”
Figure 3. Greenfield vena cava
filter.
Figure 2. Garman Kimmel,
oil-industry engineer, suggested
an implantable filter for trapping
blood clots before they can reach
the lungs.
Figure 4. Spiral Flow Vascular Access Graft (Tayside Flow
Technologies).
A. The novel graft design imparts a spiral laminar flow to the blood
delivering less turbulent flow energy to the venous anastomosis site.
B. Spiral Flow Inducer consists of an injection molded polyurethane
component that forms one 360° helical turn (HT) running along the
outside distal end of the graft.
C. Pre-cut venous anastomosis cuff.
D. Cross-section view of Spiral Flow Inducer showing injection molded
component (*).
E. Inside view of Spiral Flow Inducer showing ePTFE ridge (R) on the
graft lumen that imparts a rotational force on the blood exiting the graft
resulting in spiral laminar flow at the venous anastomosis site.
A Synergy of Industries
Tayside Flow Technologies, a small Scottish startup
company and participant in the Pumps and Pipes 3
Conference, has developed an artificial blood vessel that
mimics naturally occurring spiral flow patterns (Figure
4), thereby improving patency of bypass grafts. The same
technology is being studied to move oil through pipelines
with less frictional energy loss, thereby improving
efficiency. Indeed, pipeline engineers have long understood
the benefits of spiral flow patterns. There are other
crossovers as well. Remote monitoring, remote visualization,
3-D reconstruction of imaging data, automated
data analyses, use of simulators, robotics, and quality
improvement processes are all techniques common to
both industries, where opportunities exist for accelerated
learning.
The public was recently amazed at the clarity of visualization
and the dexterity of remote-controlled robots
in severing and capping the leaking blowout preventer
46 vII (1) 2011 | MDCvJ